Re: [OpenWrt-Devel] [PATCH] ar71xx: fix spi ath79 fast read (for 3.10 kernel)

[John Crispin]

can someone who knows m25p80 better than me figure out if this is
correct please ?



On 26/07/2014 04:52, Zhao, Gang wrote:
> Fast read adds a dummy byte in tx buffer if the transfer type is 
> SPI_TRANSFER_FLASH_READ_CMD. The dummy byte should be ignored when 
> calculating read address. This is done by adding a bool variable
> dummy in struct spi_transfer to indicate whether this transfer
> includes the dummy byte.
> 
> Signed-off-by: Zhao, Gang  --- 
> .../464-spi-ath79-fix-fast-flash-read.patch| 36
> ++ 1 file changed, 36 insertions(+) create mode
> 100644
> target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
>
>  diff --git
> a/target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
> b/target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
>
> 
new file mode 100644
> index 000..6567755 --- /dev/null +++
> b/target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
>
> 
@@ -0,0 +1,36 @@
> +--- a/drivers/mtd/devices/m25p80.c 
> b/drivers/mtd/devices/m25p80.c +@@ -360,6 +360,10 @@ static int
> m25p80_read(struct mtd_info * +   t[0].type =
> SPI_TRANSFER_FLASH_READ_CMD; +t[0].tx_buf = flash->command; +
> t[0].len = m25p_cmdsz(flash) + (flash->fast_read ? 1 : 0); ++ ++  if
> (flash->fast_read) ++ t[0].dummy = true; ++ +
> spi_message_add_tail(&t[0], &m); + +  t[1].type =
> SPI_TRANSFER_FLASH_READ_DATA; +--- a/drivers/spi/spi-ath79.c 
> b/drivers/spi/spi-ath79.c +@@ -268,6 +268,10 @@ static int
> ath79_spi_do_read_flash_cmd(s +   sp->read_addr = 0; + +  len =
> t->len - 1; ++ ++ if (t->dummy) ++len -= 1; ++ +  p = 
> t->tx_buf; 
> + +   while (len--) { +--- a/include/linux/spi/spi.h 
> b/include/linux/spi/spi.h +@@ -531,6 +531,7 @@ struct spi_transfer
> { +   u16 delay_usecs; +  u32 speed_hz; + enum 
> spi_transfer_type
> type; ++  bool dummy; + + struct list_head transfer_list; + };
> 
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[OpenWrt-Devel] [PATCH] ar71xx: fix spi ath79 fast read (for 3.10 kernel)

[Zhao, Gang]

Fast read adds a dummy byte in tx buffer if the transfer type is
SPI_TRANSFER_FLASH_READ_CMD. The dummy byte should be ignored when
calculating read address. This is done by adding a bool variable dummy
in struct spi_transfer to indicate whether this transfer includes the
dummy byte.

Signed-off-by: Zhao, Gang 
---
 .../464-spi-ath79-fix-fast-flash-read.patch| 36 ++
 1 file changed, 36 insertions(+)
 create mode 100644 
target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch

diff --git 
a/target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch 
b/target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
new file mode 100644
index 000..6567755
--- /dev/null
+++ b/target/linux/ar71xx/patches-3.10/464-spi-ath79-fix-fast-flash-read.patch
@@ -0,0 +1,36 @@
+--- a/drivers/mtd/devices/m25p80.c
 b/drivers/mtd/devices/m25p80.c
+@@ -360,6 +360,10 @@ static int m25p80_read(struct mtd_info *
+   t[0].type = SPI_TRANSFER_FLASH_READ_CMD;
+   t[0].tx_buf = flash->command;
+   t[0].len = m25p_cmdsz(flash) + (flash->fast_read ? 1 : 0);
++
++  if (flash->fast_read)
++  t[0].dummy = true;
++
+   spi_message_add_tail(&t[0], &m);
+ 
+   t[1].type = SPI_TRANSFER_FLASH_READ_DATA;
+--- a/drivers/spi/spi-ath79.c
 b/drivers/spi/spi-ath79.c
+@@ -268,6 +268,10 @@ static int ath79_spi_do_read_flash_cmd(s
+   sp->read_addr = 0;
+ 
+   len = t->len - 1;
++
++  if (t->dummy)
++  len -= 1;
++
+   p = t->tx_buf;
+ 
+   while (len--) {
+--- a/include/linux/spi/spi.h
 b/include/linux/spi/spi.h
+@@ -531,6 +531,7 @@ struct spi_transfer {
+   u16 delay_usecs;
+   u32 speed_hz;
+   enum spi_transfer_type type;
++  bool dummy;
+ 
+   struct list_head transfer_list;
+ };
-- 
1.9.3
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